The oxyhemoglobin dissociation curve (OHDC) indicates the relationship between the oxygen saturation of hemoglobin (SaO2) and the partial pressure of arterial oxygen (PaO2). Neither linear nor static, the curve can change or shift depending on various factors. Factors that shift the curve include changes in blood temperature and blood pH. Explain in details how these factors influence the affinity of hemoglobin for oxygen and affect the dissociation curve.
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- The OHDC plots percent hemoglobin saturation (SaO2) on the y-axis against the partial pressure of oxygen (PaO2) on the x-axis. - The curve is sigmoidal because hemoglobin shows cooperative binding: binding of one O2 increases the affinity for the next O2 Show more…
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A hemoglobin $\mathrm{O}_{2}$ dissociation curve: a. demonstrates that hemoglobin is about $50 \%$ saturated in the alveoli. b. shifts to the left when $\mathrm{pH}$ rises. c. demonstrates that hemoglobin holds less $\mathrm{O}_{2}$ when the $\mathrm{pH}$ is higher. d. illustrates that oxygen saturation is not dependent on $\mathrm{CO}_{2}$ levels. e. demonstrates why hemoglobin can bind $\mathrm{O}_{2}$ at high $\mathrm{pH}$ in the lungs and release it at lower $\mathrm{pH}$ in the tissues.
According to the oxyhemoglobin dissociation curve, a) When a red blood cell in a systemic capillary encounters tissue that is metabolically very active, the hemoglobin in the red blood cell releases oxygen both because the partial pressure of oxygen is relatively low and because its affinity for binding oxygen is reduced. b) Lower blood pH and higher temperatures shift the oxyhemoglobin dissociation curve to the right, facilitating oxygen unloading. This can be seen as a lowering of the oxyhemoglobin percent saturation from 60% to 40%, indicating that the difference of 20% more oxygen is unloaded to the tissues. c) When the partial pressure of oxygen is 100 mm Hg, the oxygen binding sites on both myoglobin and hemoglobin are fully saturated because myoglobin and hemoglobin have similar affinities for binding oxygen. d) Both a) and b) are correct and c) is incorrect e) a), b) and c) are all correct
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The graph shows the oxygen dissociation curve for human haemoglobin. Partial pressure of oxygen (mmHg) Draw another curve on the graph to show the oxygen dissociation curve in a location with a higher concentration of carbon dioxide, for example in an active muscle. Explain why the position of the oxygen dissociation curve for a higher carbon dioxide concentration demonstrates an important adaptation.
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